Revert deprecation of lookfor

add a basic test for it, and make sure its docstring appears in our HTMl
documentation (wasn't the case previously).

TODO.txt

@@ -3,8 +3,6 @@ Version 0.26
 * In ``skimage/morphology/gray.py``, remove deprecated parameters ``shift_x``
   and ``shift_y`` from ``erosion`` and ``dilation``, along with associated
   function ``_shift_footprint``.
-* Remove deprecated `skimage.lookfor`, `skimage/_vendored/numpy_lookfor.py`,
-  the associated note in `LICENSE.txt` and everything else associated with it.
 
 Other
 -----

doc/source/user_guide/getting_help.rst

@@ -26,6 +26,16 @@ Use the ``quick search`` field in the navigation bar of the online
 documentation to find mentions of keywords (segmentation,
 rescaling, denoising, etc.) in the documentation.
 
+
+API Discovery
+-------------
+
+We provide a ``lookfor`` function to search API functions::
+
+   import skimage as ski
+   ski.util.lookfor('eigenvalue')
+
+
 Ask for help
 ------------
 

skimage/util/__init__.py

@@ -31,6 +31,7 @@
 from .noise import random_noise
 from .shape import view_as_blocks, view_as_windows
 from .unique import unique_rows
+from .lookfor import lookfor
 
 
 __all__ = [
@@ -56,4 +57,5 @@
     'invert',
     'unique_rows',
     'label_points',
+    'lookfor',
 ]

skimage/util/lookfor.py

@@ -1,12 +1,15 @@
 import sys
 
-from .._shared.utils import deprecate_func
 from .._vendored.numpy_lookfor import lookfor as _lookfor
 
 
-@deprecate_func(deprecated_version="0.23", removed_version="0.26")
 def lookfor(what):
-    """Do a keyword search on scikit-image docstrings.
+    """Do a keyword search on scikit-image docstrings and print results.
+
+    .. warning::
+
+        This function may also print results that are not part of
+        scikit-image's public API.
 
     Parameters
     ----------
@@ -16,12 +19,12 @@ def lookfor(what):
     Examples
     --------
     >>> import skimage
-    >>> skimage.lookfor('regular_grid')  # doctest: +SKIP
+    >>> skimage.lookfor('regular_grid')
     Search results for 'regular_grid'
     ---------------------------------
-    skimage.lookfor
-        Do a keyword search on scikit-image docstrings.
     skimage.util.regular_grid
         Find `n_points` regularly spaced along `ar_shape`.
+    skimage.util.lookfor.lookfor
+        Do a keyword search on scikit-image docstrings.
     """
     return _lookfor(what, sys.modules[__name__.split('.')[0]])

skimage/util/tests/meson.build

@@ -6,6 +6,7 @@ python_sources = [
   'test_dtype.py',
   'test_invert.py',
   'test_labels.py',
+  'test_lookfor.py',
   'test_map_array.py',
   'test_montage.py',
   'test_random_noise.py',

skimage/util/tests/test_lookfor.py

@@ -0,0 +1,10 @@
+import skimage as ski
+
+
+def test_lookfor_basic(capsys):
+    assert ski.lookfor is ski.util.lookfor
+
+    ski.util.lookfor("regionprops")
+    search_results = capsys.readouterr().out
+    assert "skimage.measure.regionprops" in search_results
+    assert "skimage.measure.regionprops_table" in search_results